.338 Lapua Magnum

Initial development In 1983, Research Armament Industries (RAI) in the United States began development of a new, long-range sniper cartridge capable of firing a , bullet at , that could lethally penetrate five layers of military body armor at . After preliminary experiments, a .416 Rigby case necked down to take a bullet was selected, since this diameter presents an optimum of sectional density and penetrating capability for practical spin-stabilized rifle bullets (bullets up to about 5 to 5.5 calibers in length). The .416 Rigby is an English big-game cartridge designed in 1911 to accommodate 325 MPa (47,137 psi) pressures. One of the disadvantages of these old cartridge cases, which were intended for firing cordite charges instead of modern smokeless powder, is the thinness of the sidewall just forward of the web (the solid portion of a cartridge between the head and the bottom of the primer pocket). During ignition, the cartridge's base, just forward of the bolt face, is not supported. During the process, RAI employed Jim Bell and Brass Extrusion Labs Ltd. (B.E.L.L.) of Bensenville, Illinois, to make the .338/416 or 8.58×71 mm cartridge cases, Hornady produced bullets, and RAI built a sniper rifle under contract for the U.S. Navy. RAI found that the BELL cases did not fulfill the requirements, since they were modified low pressure .416 Rigby cases. Pressed by military deadlines, RAI looked for another case producer and contacted Lapua of Finland in 1984. RAI was forced to drop out of the program due to financial difficulties. Subsequently, Lapua of Finland put this cartridge into limited production. The .338/416 rifle program was later canceled when the contractors were unable to meet the project's velocity target of for a bullet, due to excessive pressures rupturing cartridge cases. Final development The .338 Lapua Magnum cartridge was developed as a joint venture between the Finnish rifle manufacturer SAKO and the British rifle manufacturer Accuracy International, along with the Finnish ammunition manufacturer Lapua, or more officially Nammo Lapua Oy, which since 1998 is part of the Nordic Ammunition Group (Nammo). Lapua opted to redesign the .338/416 cartridge. In the new case design, particular attention was directed toward thickening and metallurgically strengthening the case's web and sidewall immediately forward of the web. In modern solid head cases, the hardness of the brass is the major factor determining a case's pressure limit before undergoing plastic deformation. Lapua tackled this problem by creating a hardness distribution ranging from the head and web (hard) to the mouth (soft) as well as a strengthened (thicker) case web and sidewall immediately forward of the web. This resulted in a very pressure-resistant case, allowing it to operate at high pressure and come within 15 m/s (50 ft/s) of the original velocity goal. Lapua also designed a .338 caliber lock base B408 full metal jacket bullet, modeled after its .30 caliber lock base bullet configuration. The result was the .338 Lapua Magnum cartridge which was registered with C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) in 1989. With the procurement by the Dutch Army, the cartridge became NATO codified. The .338 Lapua Magnum fills the gap between weapons chambered for standard military rounds such as the 7.62×51mm NATO and large, heavy rifles firing the .50 BMG cartridge. It also offers an acceptable amount of barrel wear, which is important to military snipers who tend to fire thousands of rounds a year in practice. This was achieved by coupling a sensible case volume (7.40 ml) to bore area (56.86 mm2/0.5686 cm2) ratio (13.01 Oratio) with ample space for loading relatively long slender projectiles that can provide good aerodynamic efficiency and external ballistic performance for the projectile diameter. Like every other comparable large magnum rifle cartridge, the .338 Lapua Magnum presents a stout recoil. An appropriate fitting stock and an effective muzzle brake helps to reduce recoil-induced problems, enabling the operator to fire more rounds before getting too uncomfortable to shoot accurately. Good factory loads, multiple projectile weights and factory special application ammunition are all available. Due to its growing civilian popularity, several high-quality tactical and match (semi) custom bolt actions designed for the .338 Lapua Magnum are becoming available. These (semi) custom bolt-actions are used with other high-grade rifle and sighting components to build custom sporting and target rifles. ==Users==

Barak 338 - a militarized H-S Precision Pro Series 2000 HTR in .338 Lapua Magnum caliber The .338 Lapua Magnum cartridge is in law enforcement or military service use with: • : RENEA – Sako TRG-42 • : Blaser Tactical 2 • : Austrian Armed Forces Jagdkommando – Steyr 08A2 • : Bangladesh Armed Forces – Accuracy International AWM and Pindad SPR • : Canadian Forces – C14 Timberwolf Medium Range Sniper Weapon System (MRSWS) • : Chilean Army – APR338 and PGM 338 Barrett Model 98B • : People's Liberation Army Ground Force – QBU-202 (military designation for the 8.6×70mm CS/LR35 rifle) • : TAP. • : National Guard-Accuracy International Arctic Warfare • — Sako TRG-42 • : Military of Estonia reconnaissance units and special forces — Sako TRG-42. • : Finnish Defence Forces – Sako TRG-42 • : French Army, GIGN and Commandement des Opérations Spéciales – PGM 338, Sako TRG-42, AWM .338 • : Police and military - Accuracy International AWM and Sako TRG series, as well as Satevari MSWP. Domestic analogue .338 GBM produced by STC Delta • : – Haenel RS9 designated as G29 in service with the special forces; replacing the G22, Erma SR-100, AMP Technical Services DSR-1, GOL Sniper Magnum • : Anti-Terrorist Unit EKAM – Sako TRG-41 • : Irish Army – Accuracy International AWM .338 • : Infantry - H-S Precision Pro Series 2000 HTR Special forces — McMillan Tac-338 and PGM 338, YAMAM – Barrett MRAD • : Sako TRG-42 • : Lithuanian Armed Forces – Accuracy International AXMC • : Pasukan Gerakan Khas – Accuracy International AWM —Accuracy International AX338 • : Dutch military – Accuracy International AWM and AXMC, Sako TRG-41 • : New Zealand Defence Force – Barrett MRAD • : GROM – Accuracy International AWM, 1 Pułk Specjalny Komandosów • — Accuracy International AWM – Accuracy International AXMC • : Alpha Group, FSO and SOBR – Accuracy International AWM, ORSIS T-5000M • : Special Brigade – Sako TRG-42. • : PGM 338 • : Military of Slovenia – PGM 338 • : GOE – Sako TRG-41 • : Sako TRG-42 • : Accuracy International AWM • : Sako TRG-42 • : Used by the army snipers: the Netherlands donated Accuracy International AWM rifles to Ukraine in 2022. • : British military – Accuracy International AWM .338 • : US Navy Special Warfare – McMillan Tac-338 The .338 Lapua Magnum has been designated a "cartridge of interest" by the National Defense Industrial Association (NDIA). It is being considered to replace the .300 Winchester Magnum and the .50 BMG for anti-personnel long-range service in the U.S. military. On June 17, 2008, the U.S. government issued a market survey to support a requirement for a precision sniper rifle (PRS) to possibly replace the then-fielded bolt-action SOF Sniper Syst's0126. On 7 March 2013, the Remington MSR was declared the winner of the precision sniper rifle competition. Remington announced that the MSR had won on 8 March, and it was publicly confirmed on 9 March. This was followed by a $79.7 million contract for 5,150 rifles with suppressors, along with 4,696,800 rounds of ammunition to be supplied over the next ten years. The contract was awarded on 12 September 2013. Remington Defense would produce the Mk 21 sniper rifles and utilized two other companies for other system components, with Barnes Bullets for ammunition and Advanced Armament Corporation for muzzle brakes and suppressors; all three companies are subsidiaries of Remington Outdoor Company. However, it was then decided that the Mk 21 did not conform to SOCOM requirements, and the program was re-competed with the Barrett MRAD selected in 2019 as the Mk 22 Advanced Sniper Rifle solution. The US military opted to use 7.62×51mm NATO, .300 Norma Magnum and instead of the .338 Lapua Magnum the .338 Norma Magnum chambering in their Mk 22 rifles, which have a field-convertible barrel/chambering switch capability. ==Cartridge dimensions==

Extremely thick-walled brass results in a 7.40 ml (114 grains H2O) cartridge case capacity for the .338 Lapua Magnum. The exterior shape of the case was designed to promote reliable feeding and extraction in bolt action, semi-automatic, and automatic firearms alike, under extreme conditions. .338 Lapua Magnum maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm). Americans define the shoulder angle at alpha/2 ≈ 20 degrees. The common rifling twist rate for this cartridge is 254 mm (1 in 10 in), 6 grooves, Ø lands = 8.38 mm, Ø grooves = 8.58 mm, land width = 2.79 mm and the primer type is large rifle magnum. According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) decisions and tables edition 2007 the .338 Lapua Magnum case can handle up to Pmax piezo pressure. This prevails over the C.I.P. decisions and tables edition 2003, that rated the .338 Lapua Magnum at Pmax maximum piezo pressure. The Pmax maximum piezo pressure C.I.P. ruling for the .300 Lapua Magnum cartridge, which is based on the same case, was at the time not accordingly changed. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of the prevailing maximum C.I.P. pressure to certify for sale to consumers. This means that .338 Lapua Magnum chambered arms in C.I.P. regulated countries are proof tested at PE piezo pressure. Lapua has been ambivalent on the maximum piezo pressure of this cartridge. In the article "From an American dream to a Finnish success story" by Janne Pohjoispää, Lapua propagates the C.I.P. 2007 ruling of maximum piezo pressure. To further complicate matters the mentioned 56,000 CUP C.I.P. copper crusher pressure translates to around C.I.P. piezo pressure according to a study on the conversion from CUP to PSI for rifle cartridges by Denton Bramwell. The C.I.P. 2003 ruling of piezo pressure is corroborated by Lapua Australia in the "History and development of the .338 Lapua Magnum" article by Alan C. Paulson. A reverse engineering simulation with QuickLOAD internal ballistic software predicted that Lapua load their factory .338 Lapua Magnum ammunition at about piezo pressure, as Paulson asserts in his article. The large bolt face combined with the maximum pressure means that the .338 Lapua Magnum is normally only chambered in rifles that are capable of handling such large high-pressure cartridges, and thus high bolt thrust, safely. Chambering such powerful super magnum cartridges in rifles intended for normal magnum rifle cartridges and using high-pressure loads can cause serious or fatal injury to the shooter and bystanders. The American .338-378 Weatherby Magnum cartridge introduced in 1998 and the American .338 Remington Ultra Magnum (.338 RUM) cartridge introduced in 2000 are probably the closest ballistics-wise to the .338 Lapua Magnum commercially available . The .338-378 Weatherby Magnum is, however, a belted cartridge and the .338 Remington Ultra Magnum is a rebated rim cartridge. The American SAAMI (Sporting Arms and Ammunition Manufacturers' Institute) has no normal voluntary guidelines for the .338 Lapua Magnum. On 14 January 2013 it opted to use the metric C.I.P. rulings and add some dimensions that have no C.I.P. analog. ==Supersonic range performance of the .338 Lapua Magnum==

Performance with C.I.P. conforming cartridges For a typical .338 Lapua Magnum high-end factory military sniper rifle like the Sako TRG-42 with a long 305 mm (1 in 12 inch) rifling twist rate barrel at sea level, is considered to be the maximum shooting distance for man-sized targets. When using standard Lapua military 16.2 g (250 gr) loads it has a supersonic range of under warm summer conditions at a muzzle velocity of . However, to be able to maintain 80 to 90% hit probability on non-moving reactive army targets, this maximum shooting distance has to be reduced to at freezing point conditions or in Arctic winter conditions, when the muzzle velocity may drop to —i.e. only during optimal warm summer conditions the maximum shooting distance is realistically achievable. Loaded with more aerodynamic very-low-drag bullets such as the traditionally lead-cored 19.44 g (300 gr) Lapua Scenar GB528 VLD bullet (G1 BC = 0.736) or the Lost River Ballistics J40 .338 17.5 gram (270 gr) CNC manufactured mono-metal bullet (G1 BC = 0.871) the long-range performance and supersonic range of .338 Lapua Magnum rifles can be improved. These longer very-low-drag bullets require a 254 mm (1 in 10 inch) twist rate to stabilize them. Due to the lower practically possible muzzle velocities for a relative heavy bullet like the 19.44 g (300 gr) Lapua Scenar GB528 VLD bullet it gains about extra supersonic range under International Standard Atmosphere sea level conditions (air density ρ = 1.225 kg/m3) at a muzzle velocity of 837 m/s (2750 ft/s) when compared to the standard 16.2 g (250 gr) Lapua Scenar GB488 VLD at a muzzle velocity of 915 m/s (3002 ft/s). For significant supersonic range improvement, the aerodynamic efficiency of the employed bullets has to be significantly improved without sacrificing a lot of practically achievable muzzle velocity - meaning that besides the coefficient of drag of the projectile weight is also an important parameter for its actual downrange flight behavior. The .338 17.5 gram (270 gr) Lost River Ballistic Technologies J40 match bullet made out of a copper-nickel alloy is one of the most aerodynamic .338 calibre bullets available. It has an supersonic range under optimal warm summer conditions at a muzzle velocity of . This makes engaging static targets up to feasible. Performance improvement experiments with non-C.I.P.-conforming cartridges Improvement beyond this standard while still using standard .338 Lapua Magnum brass is possible, but the bullets have to be very long (over 5.5 calibers in length) and the normal cartridge overall length of 93.5 mm has to be exceeded, making such cartridges wildcats. The common 254 mm (1:10 inch) rifling twist rate also has to be tightened to stabilize very long projectiles. Such commercially non-existent cartridges are termed "wildcats". The use of a wildcat .338 Lapua Magnum-based cartridge demands the use of a custom or customized rifle with an appropriately cut chamber and fast-twist bore. The firearm action and if a repeating arm is required the magazines must also be able to cope with dimensional increases. An example of such a special .338 caliber extreme range bullet is the German CNC manufactured mono-metal 18.92 gram (292 gr) LM-105 (Cd = 0.2487 at Mach 2.216 – this drag coefficient and the corresponding G1, G7 and G8 ballistic coefficients are established by Doppler radar measurements). The LM-105 has a supersonic range of ≈ at a muzzle velocity of under International Standard Atmosphere sea level conditions (air density ρ = 1.225 kg/m3). The 2010 version of the LM-105 bullet has an overall length of or 6.33 calibers and derives its exceptionally low drag from a radical LD Haack or Sears-Haack profile in the bullet's nose area. Rifles chambered for this wildcat cartridge, with a cartridge overall length of , and equipped with custom made 178 mm (1:7 inch) progressive twist rate long barrels with a 2° cone-angle (the standard C.I.P. cone-angle for the .338 Lapua Magnum is 6°) cone area finished first and second at several long-range competitions. Its most recent win (2007) was in an international special forces and police sniper competition in Switzerland against rifles chambered for 7.62×51mm NATO up to .50 BMG at ranges from 100 m – 1,500 m (109 yd – 1,640 yds). The LM-105 bullet exhibited its very low wind drift susceptibility notably at ranges beyond . The LM-107 was hoped to boost the ballistic performance of the LM-105 by achieving an increase in supersonic range. The 19.3 g (298 gr) LM-107 projectile design is long and has a Haack profiled nose and an Adams profiled tail. The rifling twist rate for the .343 Lapua Magnum LM-107 wildcat cartridge was chosen at 180 mm (1:7 inch), Ø lands = 8.72 mm, Ø grooves = 8.45 mm and loaded with the LM-107 projectile has a cartridge overall length of . The length of the neck is increased from 8,31 to 8,50 mm to support the bigger LM-107 bullet. Several other dimensions of the .338 Lapua Magnum parental cartridge are also changed. The shoulder angle gets steepened from 40° to 60° and the body taper is set at 1°. The throat area is set at a 2° cone-angle. All these modifications make the .343 Lapua Magnum a fairly comprehensively revised wildcat cartridge. Out of a long progressive twist barrel Möller expected to achieve muzzle velocity. If Möller's design assumptions are correct the LM-107 projectile with a calculated G1 BC of 1.02 will offer a supersonic range of ≈ at a muzzle velocity of under International Standard Atmosphere sea level conditions (air density ρ = 1.225 kg/m3). ==As a parent case==

.300 Lapua Magnum The commercially successful .338 Lapua Magnum cartridge has functioned as the parent case for the .300 Lapua Magnum, which is essentially a necked-down version of the .338 Lapua Magnum. The .338 cartridge case was used for this since it has the capability to operate with high chamber pressures which, combined with smaller and hence lighter bullets, result in very high muzzle velocities. The Finnish ammunition manufacturer Lapua got the .300 Lapua Magnum C.I.P. certified, so it became an officially registered and sanctioned member of the Finnish "family" of super magnum rifle cartridges. The .300 Lapua Magnum is not commercially available and exists only as a C.I.P. datasheet. It is however still used by a few shooters who produce the cases from .338 Lapua Magnum brass by reshaping the shoulder and neck, and handloading it with .30 calibre bullets. The .300 Lapua Magnum has a 7.33 ml (113 grains H2O) cartridge case capacity. .300 Lapua Magnum maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm). Americans define the shoulder angle at alpha/2 ≈ 25 degrees. The common rifling twist rate for this cartridge is 240 mm (1 in 9.45 in), 4 grooves, Ø lands = 7.62 mm, Ø grooves = 7.82 mm, land width = 4.47 mm and the primer type is large rifle magnum. According to the official C.I.P. rulings the .300 Lapua Magnum can handle up to Pmax piezo pressure. This prevails over the C.I.P. decisions and tables edition 2007, that rated the .300 Lapua Magnum at Pmax piezo pressure. The large diameter bolt face, combined with the high maximum pressure, means that the .300 Lapua Magnum is normally only chambered in rifles that are capable of handling the resulting high bolt thrust, safely. Chambering such powerful super magnum cartridges in rifles intended for normal magnum rifle cartridges and using loads can cause serious or fatal injury to the shooter and bystanders. 7.62 UKM The .338 Lapua Magnum cartridge is also used as the parent case for the German-designed 7.62 UKM, which is essentially a necked-down shortened version of the .338 Lapua Magnum. The use of the .338 cartridge case with its capability to operate at high chamber pressures resulted in a magnum case capable of producing high muzzle velocities. The 7.62 UKM was developed by Michael Uekötter and was C.I.P.-certified in 2002, making it an officially registered and sanctioned member of the Finnish "family" of super magnum rifle cartridges. The 7.62 UKM is not commercially available and exists only as a C.I.P. datasheet. It is however still used by a few shooters who produce the cases from .338 Lapua Magnum brass by reshaping the shoulder and neck, and handloading it with .30 caliber bullets. The 7.62 UKM has a 5.84 ml (90 grains H2O) cartridge case capacity. 7.62 UKM maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm). Americans define the shoulder angle at alpha/2 ≈ 20 degrees. The common rifling twist rate for this cartridge is 254 mm (1 in 10 in), 6 grooves, Ø lands = 7.62 mm, Ø grooves = 7.82 mm, land width = 2.79 mm and the primer type is large rifle magnum. According to the official C.I.P. rulings the 7.62 UKM Magnum can handle up to Pmax piezo pressure. This prevails over the C.I.P. decisions and tables edition 2007, that rated the 7.62 UKM at Pmax piezo pressure. .375 Swiss P The .375 Swiss P (9.5×7 0mm) is a C.I.P. registered chambering introduced in 2021 and advertised by RUAG Ammotec as a cartridge that "fills the gap in ballistic performance between the .338 Lapua Magnum (8.6×70 mm) and the .50 BMG (12.7×99mm NATO)". As such, .375 Swiss P was designed to be relatively easily rechambered by a rebarreling as a performance upgrade in sturdily built rifles originally designed around the .338 Lapua Magnum chambering. The .375 Swiss P is a rebated rim bottlenecked cartridge that shares its bolt face, rim diameter, overall length, and maximum operating pressure with the .338 Lapua Magnum chambering. It features a larger base diameter as found in the .500 Jeffery. This results in a (P1 - R1 = ) rebated rim. Wildcats The .338 Lapua Magnum case is also used as the parent case for a host of modified variants that are not officially registered with or sanctioned by C.I.P. or its American equivalent, SAAMI. By changing the shape of standard factory cases (decreasing case taper or changing the shoulder geometry) the wildcatter generally increases the case capacity of the factory parent cartridge case, allowing more propellant to be used to generate higher velocities. Besides changing the shape and internal volume of the parent cartridge case, wildcatters also can change the original caliber. Because the .338 Lapua offers a large and exceptionally sturdy, pressure-resistant cartridge case that can be relatively easily reloaded and hence be reused several times, it has become quite popular amongst wildcatters. With the .338 Lapua Magnum as the parent case wildcatters have created 7 mm (7 mm Allen Magnum, 7 mm Katzmeier, 7 mm Fatso), .30 (.30-338 Lapua (Triebel), .30 Wolf, 300 Allen Express), 8 mm (8 mm-338 Lapua (Triebel), LM-101), .338 (.338 Yogi, LM-105), .343 (.343 Lapua Magnum LM-107 ==See also==